airport link bus should be fine, they've loads of room for luggage and super cheap. A big taxi will do the job too, will cost more but might be easier if you're not on the bus route. We got 3 of us and bikes in a large taxi a couple of weeks ago.

I've heard, but never used the park and ride car park at the FRB, that the parking there is free and that many air travelers use it as a free long stay car park simply catching the bus to the airport.

I do that if I'm away for between 2 and 7 days. You have to leave your details and your only allowed to leave the car in the multistory bit and only for up to 7 days. Handy if your coming from the north.